Jin Cheon Kim

LYMPH NODE RATIO AS A PROGNOSTIC FACTOR IN PATIENTS WITH STAGE III RECTAL CANCER TREATED WITH TOTAL MESORECTAL EXCISION FOLLOWED BY CHEMORADIOTHERAPY

PURPOSEnTo investigate the prognostic impact of lymph node ratio (LNR) on survival in the patients with Stage III rectal cancer.nnnMETHODS AND MATERIALSnWe retrospectively reviewed the data of 421 consecutive patients who underwent total mesorectal excision followed by chemoradiotherapy for rectal cancer from 1996 to 2006. The 232 patients with positive lymph nodes (LNs) were divided into four groups according to LNR quartiles: LNR <or=0.1 (n = 69), <or=0.2 (n = 49), <or=0.4 (n = 54), and >0.4 (n = 60). The association between LNR and survival was evaluated by the Kaplan-Meier method and multivariate analysis with covariates of prognostic significance in univariate analysis.nnnRESULTSnThe median numbers of examined and positive LNs were 17 and 3, respectively, and the median LNR was 0.20 (range, 0.03-1). There was a strong correlation between the number of positive LNs and LNR (r = 0.724, p < 0.001). After a median follow-up of 53 months (range, 9-138 months), the actuarial overall survival and disease-free survival rates at 5 years were 69% and 56%, respectively. The 5-year survival rate decreased as LNR increased (<or=0.1, 89%; <or=0.2, 67%; <or=0.4, 64%; >0.4, 50%; p < 0.001). Lymph node ratio was also a significant prognostic factor on Cox regression analysis (<or=0.1, hazard ratio [HR] = 1; <or=0.2, HR = 1.3, p = 0.623; <or=0.4, HR = 2.4, p = 0.047; >0.4, HR = 3.7, p = 0.005). Lymph node ratio had a prognostic effect on overall survival in subgroups of patients with N1 (p = 0.032) and N2 (p = 0.034) tumors.nnnCONCLUSIONnLymph node ratio was the most significant predictor of survival in the patients with Stage III rectal cancer who had undergone postoperative chemoradiation.

Poorly Differentiated Colorectal Cancers

OBJECTIVESnTo evaluate the association of microsatellite instability (MSI) with clinicopathologic features and oncologic outcomes in patients with poorly differentiated colorectal cancer (PD).nnnMETHODSnStudy patients were divided into well-differentiated colorectal cancer (WD) and PD, which were compared according to histologic differentiation and MSI status.nnnRESULTSnAmong 1,941 patients, PD was more frequent among microsatellite-unstable tumors (23.6%) than among microsatellite-stable (MSS) tumors (4.2%, P < .001). Patients with PD had worse 4-year overall survival rates than patients with WD (78.6% vs 88.2%, P = 0.010). Compared with MSS-PD tumors, MSI-PD tumors were characterized by right-colon predilection, larger size, and infrequent lymph node metastasis (P < .001 to P = .007).nnnCONCLUSIONSnThe clinicopathologic characteristics of PD were closely associated with those of MSI. The outcomes of MSI-PD tumors were better than those of MSS-PD tumors, but this finding did not reach statistical significance.

Polypyrimidine tract-binding protein 1-mediated down-regulation of ATG10 facilitates metastasis of colorectal cancer cells.

Autophagy plays complex roles in tumor initiation and development, and the expression of autophagy-related genes (ATGs) is differentially regulated in various cancer cells, depending on their environment. In this study, we analyzed the expressional relationship between polypyrimidine tract-binding protein 1 (PTBP1) and ATG10 in metastatic colorectal cancer. PTBP1 is associated with tumor metastasis in primary colorectal tumors and colorectal cancer liver metastasis (CLM) tissues. In addition, PTPB1 directly interacts with mRNA of ATG10, and regulates ATG10 expression level in colorectal cancer cells. Ectopic expression of PTBP1 decreased ATG10 expression, whereas down-regulation of PTBP1 increased ATG10 level. In contrast to PTBP1, expression of ATG10 was decreased in CLM tissues. Knock down of ATG10 promoted cell migration and invasion of colorectal cancer cells. Moreover, depletion of ATG10 modulated epithelial-mesenchymal transition-associated proteins in colorectal cancer cells: N-cadherin, TCF-8/ZEB1, and CD44 were up-regulated, whereas E-cadherin was down-regulated. Taken together, our findings suggest that expression of ATG10 negatively regulated by PTBP1 is associated with metastasis of colorectal cancer cells.

Complex Behavior of ALDH1A1 and IGFBP1 in Liver Metastasis from a Colorectal Cancer

Using our data set (GSE50760) previously established by RNA sequencing, the present study aimed to identify upregulated genes associated with colorectal cancer (CRC) liver metastasis (CLM) and verify their biological behavior. The potential roles of candidate genes in tumors were assessed using cell proliferation and invasion assays. Tissue samples were collected from 18 CRC patients with synchronous CLM and two CRC cell lines (SW480 and SW620) were used for transfection and cloning. The roles of the genes identified in CLM were verified using immunohistochemistry in 48 nude mice after intrasplenic transplantation of CRC cells. mRNA and protein expression was determined by quantitative real-time reverse transcription polymerase chain reaction and western blot, respectively. Nine genes were initially selected according to the relevance of their molecular function and biological process and, finally, ALDH1A1 and IGFBP1 were chosen based on differential mRNA expression and a positive correlation with protein expression. The overexpression of ALDH1A1 and IGFBP1 significantly and time-dependently decreased cell proliferation (p ≤ 0.001–0.003) and suppressed invasiveness by ≥3-fold over control cells (p < 0.001) in the SW480 cell line, whereas they had a slight effect on reducing SW620 cell proliferation. The protein expression levels of E-cadherin, N-cadherin, claudin-1, and vimentin were significantly higher in CLM than in primary tumor tissues (p < 0.05). However, the cadherin switch, namely, N-cadherin overexpression with reduced E-cadherin expression, was not observed in CLM tissues and transfected CRC cells. Irrespective of reduced proliferation and invasion found on in vitro cell assays, persistent overexpression of β-catenin, vimentin, and ZO-1 in IGFBP1-overexpressing SW480 cells possibly contributed to CLM development in mice implanted with IGFBP1-overexpressing SW480 cells (CLM occurrences: SW480/IGFBP1-transfected mice vs. SW480/vector- and SW480/ALDH1A1-transfected mice, 4/8 vs. 0/10, p = 0.023). In conclusion, ALDH1A1 and IGFBP1 are differentially overexpressed in CLM and may play a dual role, functioning as both tumor suppressors and metastasis promoters in CRC.

Comparative analysis focusing on surgical and early oncological outcomes of open, laparoscopy-assisted, and robot-assisted approaches in rectal cancer patients

PurposeBecause there are few comparative studies of open, laparoscopy-assisted (LA), and robot-assisted (RA) total mesorectal excision (TME) for rectal cancer, we aimed to compare these three procedures in terms of sphincter-saving operation (SSO) achievement, surgical complications, and early oncological outcomes.MethodsThe short-term outcomes of 2114 patients with rectal cancer consecutively enrolled between July 2010 and February 2015 at Asan Medical Center (Seoul, Korea) were retrospectively evaluated. Patients underwent either open, LA, or RA TME (nu2009=u20091095, 486, and 533, respectively) performed by experienced surgeons.ResultsRA TME was a significant determinant of SSO in multivariate analysis that included potential variables such as tumor location and T4 category (odds ratio, 2.458; 95xa0% confidence interval, 1.497–4.036; pu2009<u20090.001). The cumulative rates of 3-year local recurrence, overall survival, and disease-free survival did not differ among the three groups: 2.5–3.4, 91.9–94.6, and 82.2–83.1xa0% (pu2009=u20090.85, 0.352, and 0.944, respectively). Early general surgical complications occurred more frequently in the open group than in the LA and RA groups (19.3 versus 13.0 versus 12.2xa0%, pu2009<u20090.001), specifically ileus and wound infection.ConclusionsThere were no significant differences in 3-year survival outcomes and local recurrence among open, LA, and RA TME. RA TME is useful for SSO achievement, regardless of advanced stage and location of rectal cancer. The open procedure had a slightly but significantly higher incidence of postoperative complications than LA and RA.

The prognostic significance and treatment modality for elevated pre- and postoperative serum CEA in colorectal cancer patients

Purpose The purpose of this study was to evaluate the prognostic significance of serum CEA (s-CEA) changes in colorectal cancer (CRC) patients with sustained elevated postoperative s-CEA levels. Methods Between January 1999 and December 2008, 9,380 CRC patients underwent surgery. Curative resection was performed in 1,242 CRC patients with high preoperative s-CEA levels (>6 ng/mL). High s-CEA levels were normalized in 924 patients (74.4%) within 2 weeks from surgery, whereas high s-CEA levels were persistent in 318 patients (25.6%). Patients were divided into 2 groups according to their postoperative s-CEA levels: group 1 (37 patients with a 1-year postoperative s-CEA>6 ng/mL) and group 2 (281 patients with a 1-year postoperative s-CEA≤6 ng/mL). Results A postoperative recurrence was identified in 24 patients (64.9%) in group 1 and 65 patients (23.1%) in group 2 (P < 0.001). A curative resection after recurrence was performed in 22 patients (33.8%) from group 2, but no patients from group 1 (P = 0.001). The 5-year overall survival and time to recurrence were significantly lower in patients with recurrent cancer in group 1 (P < 0.001). Conclusion Patients with persistent elevated postoperative s-CEA levels are at high risk for recurrence and a low survival rate. More intensive surveillance of patients with high postoperative s-CEA levels should be mandatory.

PSMB8 as a Candidate Marker of Responsiveness to Preoperative Radiation Therapy in Rectal Cancer Patients

PURPOSEnThe ability to predict individual responsiveness to cancer therapy is urgently needed. This is particularly true for patients with locally advanced rectal cancer (LARC) because a large proportion are resistant to preoperative chemoradiation therapy (CRT). In this study, we sought to identify markers that could predict response by comparing the gene expression profiles of the tumors of patients who received preoperative CRT.nnnMETHODS AND MATERIALSnThe basal gene expression profiles of tumors from 22 LARC patients who were responders (n=9) and nonresponders (n=13) to preoperative CRT were analyzed using RNA sequencing (RNA-Seq). To validate the RNA-Seq findings, real-time reverse transcriptase polymerase chain reaction (RT-PCR) was performed on tumor samples from an additional 40 LARC patients (n=20 responders; n=20 nonresponders). Candidate genes were stably overexpressed or knocked down in colorectal cancer (CRC) cell lines, and the effect on response to radiation was tested inxa0vitro and also inxa0vivo in a mouse xenograft model.nnnRESULTSnEight differentially expressed (>16-fold) genes (B3GALT4, HSPA1B, KRBOX1, PPBP, PPP1R18, PSMB8, SLC39A7, and TAP2) associated with the preoperative CRT response were identified (P<.0005). Among these genes, real-time RT-PCR showed that PSMB8 and SLC39A7 were upregulated in the responsive group of the additional 40 LARC patients. In CRC cell lines, PSMB8 overexpression significantly reduced colony formation and increased the apoptosis-inducing molecules cleaved caspase-3 and cleaved PARP after 6-Gy irradiation. PSMB8 knockdown increased colony formation and decreased caspase-3 activation and cleaved PARP levels after irradiation. SLC39A7 overexpression had no significant effects on irradiated CSC cells. After irradiation of the xenografted mice, tumors that arose from CRC cell line HCT116 overexpressing PSMB8 grew more slowly than did those from HCT116 with vector alone.nnnCONCLUSIONnThese results suggest that PSMB8 is a predictive marker of preoperative radiosensitivity in LARC patients. Clinical validation in a larger cohort is now required.

Feasibility of novel PPP1R15A and proposed ANXA11 single nucleotide polymorphisms as predictive markers for bevacizumab regimen in metastatic colorectal cancer.

PurposeBevacizumab improves survival in patients with metastatic colorectal cancer (mCRC) under chemotherapy, but few predictive markers have been identified.MethodsTo investigate chemosensitive single nucleotide polymorphisms (SNPs) of mCRC, we performed exome sequencing and RNA sequencing in 19 patients. A clinical association analysis was performed with the other 116 patients who had received chemotherapy to bevacizumab regimens. In vivo biodistribution studies and [18F]FDG-PET imaging were performed on mice bearing human colorectal cancer (HCT116 and SW480) xenografts after injection of bevacizumab with 5-FU, leucovorin, and irinotecan (FOLFIRI).ResultsPPP1R15Ars557806 showed the most significant association with FRB-driven tumor IR in exome sequencing and the highest correlation (rxa0=xa00.74) with drug responses in RNA sequencing. Patients homozygous for the reference alleles (GG) of PPP1R15A rs557806 exhibited greater disease control rate and a tendency toward greater objective response rate (ORR) than those with homozygous or heterozygous substitution alleles (GC and CC; Pxa0=xa00.027 and 0.073, respectively). In xenografted mice, HCT116 clones transfected with the G allele at PPP1R15A rs557806 were more sensitive to bevacizumab regimens than those with the C allele. Tumor volume of xenografts with the G allele was significantly lower than that of xenografts with the C allele (Pxa0=xa00.004, day 13). [18F]FDG uptake decreased to 75xa0% in HCT116 xenograft-bearing mice with the G allele, whereas [18F]FDG uptake was 42xa0% in mice xenografts with the C allele (Pxa0=xa00.032). ANXA11 rs1049550, a predictive biomarker of SNP described in our previous study, was validated using the xenograft model. Tumor volume and [18F]FDG uptake analyses showed that tumors in the SW480 xenografts expressing the substitution allele (T) at ANXA11 rs1049550 were more susceptible to FOLFIRI plus bevacizumab-induced suppression than those expressing the reference allele (C) (Pxa0=xa00.001 and 0.026, respectively).ConclusionANXA11 rs1049550 and PPP1R15A rs557806 may improve the identification of mCRC patients sensitive to bevacizumab regimens, and further validation is required in large cohorts.

Opposite functions of GSN and OAS2 on colorectal cancer metastasis, mediating perineural and lymphovascular invasion, respectively

The present study aimed to identify molecules associated with lymphovascular invasion (LVI) and perineural invasion (PNI) and to examine their biological behavior in colorectal cancer (CRC). LVI- and PNI-associated molecules were identified and verified using sequential processes including (1) identification of 117 recurrence-associated genes differentially expressed on RNA-seq analysis using primary cancer tissues from 130 CRC patients with and without systemic recurrence; (2) analysis of molecules associated with LVI and PNI; (3) assessment of biological properties by measuring proliferation, anoikis, invasion/migration, epithelial-mesenchymal transition and autophagy flux; and (4) verification of disease-free survival using public datasets. Gelsolin (GSN) and 2-5-oligoadenylate synthetase 2 (OAS2) were associated with PNI and LVI, respectively. Invasion potential was >2-fold greater in GSN-overexpressing LoVo cells than in control cells (p<0.001–0.005), whereas OAS2-overexpressing RKO cells showed reduced invasion (p<0.001–0.005). GSN downregulated E-cadherin, β-catenin, claudin-1 and snail, and upregulated N-cadherin and ZEB1, whereas OAS2 overexpression had the opposite effects. Several autophagy-related proteins including ATG5-12, ATG6/BECN1, ATG7 and ATG101 were downregulated in GSN-overexpressing LoVo cells, whereas the opposite pattern was observed in OAS2-overexpressing RKO cells. Patients with low GSN expression had significantly higher 5-year recurrence-free survival (RFS) rates than those with GSN overexpression (73.6% vs. 64.7%, p = 0.038), whereas RFS was longer in patients with OAS2 overexpression than in those with underexpression (73.4% vs. 63.7%, p = 0.01). In conclusion, GSN and OAS2 were positively and negatively associated with recurrence, respectively, suggesting their potential value as predictors of recurrence or therapeutic targets in CRC patients.

Abstract 4992: Zkscan3 facilitates invasion of colorectal cancer associated with ceacam5

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CAnnPurpose: ZKSCAN3 is over-expressed in invasive colonic tumor cells and regulate the expression of several genes favoring tumor progression including integrin β4. We evaluated the role of ZKSCAN3 in invasive signaling pathway with stage 4 colorectal cancer (CRC).nnMaterials and methods: 119 metastatic CRC (mCRC) patients who palliatively or curatively resected and 331 sporadic CRC patients who curatively resected from January 2004 to December 2009 were used to identify correlations between single-nucleotide polymorphism (SNP) rs733743 and clinically prognostic parameters. To validation of prior correlation, the genotypes of SNP identified by pyrosequencing using 81 patients (33 with mCRC and 48 CRC patients) and CRC cell lines. We then performed immunohistochemistry (IHC) and Western blot on 36 mCRC patients and 49 CRC patients. Up-regulated putative down-stream targets included genes contributing tumor aggressiveness and invasiveness; VEGF, cyclin D2, Akt, phospho-Akt, integrin β4, KRAS, CEACAM5, and integrin α5β1. To test biological utility assay, ZKSCAN3 mRNA was knocked down by ZKSCAN3 specific siRNA in metastatic CRC cells (LOVO) and ZKSCAN3 cDNA was overexpressed in the low-ZKSCAN3 expressed CRC cells (HCT116).nnResults: Wild-type alleles (GG) of ZKSCAN3 rs733743 was related with male dominant, family history of malignancy, high CEA concentration, and mCRC. The wild-type alleles of ZKSCAN3 rs733743 using tissue sample was related with lymphvascular invasion. ZKSCAN3 IHC positive tissue was related with lymphovascular invasion. ZKSCAN expression was higher in LOVO and SW620 cell lines which were derived from metastatic site. ZKSCAN3 high groups were related with CEA, integrin β4, VEGF, and AKT and ZKSCAN3 low groups were related with RAS, VEGF, AKT, and PAKT in metastatic tumor tissue. Therefore, ZKSCAN3 seemed to be related with CEA and integrin β4 to metastasis. Additional CEA expression was observed a significant decrease in ZKSCAN3 knockdowned LOVO cell (1.0 vs 0.89, P= 0.046) and invasiveness of the ZKSCAN3 overexpressed HCT116 cells was higher in CEA coated filters (75.6±6.0 vs 91.3±4.5, P=0.023).nnConclusion: ZKSCAN3 is related with colorectal tumor progression and invasion. ZKSCAN3 overexpression tumor may facilitate metastasis of colorectal cancer associated with CEACAM5.nnCitation Format: Seon Ae Roh, Chan Wook Kim, Ka Hee Tak, Jin Cheon Kim. Zkscan3 facilitates invasion of colorectal cancer associated with ceacam5. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4992. doi:10.1158/1538-7445.AM2014-4992